New results using the Herschel Space Telescope suggest that Earth’s water was brought here by comets.
More evidence that there are active flows of water on Mars.
Dark, finger-like features appear and extend down some Martian slopes during late spring through summer, fade in winter, and return during the next spring. Repeated observations have tracked the seasonal changes in these recurring features on several steep slopes in the middle latitudes of Mars’ southern hemisphere.
Though there are a number of unsolved issues about these features, the best explanation appears to be a liquid brine.
Saltiness lowers the freezing temperature of water. Sites with active flows get warm enough, even in the shallow subsurface, to sustain liquid water that is about as salty as Earth’s oceans, while pure water would freeze at the observed temperatures.
Go here to see the full image.
The Herschel space telescope has discovered that the water expelled from the tiger stripes on Enceladus eventually rains down on Saturn.
Enceladus expels around 250 kg of water vapour every second, through a collection of jets from the south polar region known as the Tiger Stripes because of their distinctive surface markings. These crucial observations reveal that the water creates a doughnut-shaped torus of vapour surrounding the ringed planet. The total width of the torus is more than 10 times the radius of Saturn, yet it is only about one Saturn radius thick. Enceladus orbits the planet at a distance of about four Saturn radii, replenishing the torus with its jets of water.
Since the 1990s, scientists have suspected that water-ice might be hidden in the forever-dark floors of the polar craters on the Moon. If so, these locations become valuable real estate, as they not only would provide future settlers water for drinking, the water itself can be processed to provide oxygen and fuel.
Moreover, the high points near these craters, including the crater rims, are hoped to be high enough so that the sun would never set or be blocked by other mountains as it made its circuit low along the horizon each day. If such a place existed, solar panels could be mounted there to generate electricity continuously, even during the long 14-day lunar night.
Below the fold is a six minute video, produced from images taken by Lunar Reconnaissance Orbiter (LRO) from February 6, 2010 to February 6, 2011, in an effort to find out if such a place actually exists. It shows how the sunlight hits the south pole across an entire year.
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Mining the moon for water and fuel.
Texas-based Shackleton Energy Company has already begun operations aimed at mining the Moon within the next few years. The company’s plans for mining and refining operations would involve melting the ice and purifying the water, converting the water into gaseous hydrogen and oxygen, and then condensing the gases into liquid hydrogen, liquid oxygen and hydrogen peroxide, all potential rocket fuels.
Shackleton CEO Dale Tietz says the water extracted would be used almost exclusively as rocket fuel to power operations both within Low Earth Orbit (LEO) – such as space tourism and the removal of space-debris – on the Moon, and further out into space. ‘We are a for-profit business enterprise moving forward, and so we are only going there really for one reason and that is to mine, prospect mine and harvest water for rocket propellant production,’ says Tietz.
Cassini has directly sampled the plumes from Enceladus and discovered a salty ocean-like spray.
The new paper analyzes three Enceladus flybys in 2008 and 2009 with the same instrument, focusing on the composition of freshly ejected plume grains. The icy particles hit the detector target at speeds between 15,000 and 39,000 mph (23,000 and 63,000 kilometers per hour), vaporizing instantly. Electrical fields inside the cosmic dust analyzer separated the various constituents of the impact cloud.
The data suggest a layer of water between the moon’s rocky core and its icy mantle, possibly as deep as about 50 miles (80 kilometers) beneath the surface. As this water washes against the rocks, it dissolves salt compounds and rises through fractures in the overlying ice to form reserves nearer the surface. If the outermost layer cracks open, the decrease in pressure from these reserves to space causes a plume to shoot out. Roughly 400 pounds (200 kilograms) of water vapor is lost every second in the plumes, with smaller amounts being lost as ice grains. The team calculates the water reserves must have large evaporating surfaces, or they would freeze easily and stop the plumes.
A new analysis of a moon rock brought back by Apollo 17 has suggested that the water content of lunar magma is 100 times higher than previously thought.
Truly alien: The strange egg-shaped dwarf planet Haumea is apparently also covered with crystallised ice.
“Since solar radiation constantly destroys the crystalline structure of ice on the surface, energy sources are required to keep it organized. The two that we have taken into consideration are that able to generate radiogenic elements (potassium-40, thorium-232 and uranium-238) from the inside, and the tidal forces between Haumea and its satellites,” [explained] Benoit Carry, co-author of the study and a researcher at the ESAC Centre of the European Space Agency (ESA) in Madrid (Spain).
Scientists have found evidence that a subsurface ocean of water and ammonia exists within Saturn’s moon Titan.
Above, an annotated version of the first orbital image, showing areas of the south pole never before seen.
From the press conference about the first Messenger images from Mercury orbit:
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The image below from Mars Reconnaissance Orbiter shows gullies remarkably similar to gullies formed on Earth by flowing water, thus providing striking evidence that at some time in the past liquid water did flow on the Martian surface, something that is not possible now. Key quote from the caption:
The gullies shown in the subimage (approximately 710 x 1100 yards) have well developed alcoves, deeply incised channels, and large depositional fans, and are similar to terrestrial landscapes sculpted by surficial water.
The gullies shown in the subimage experienced several periods of activity, as evidenced by older channels cut by younger ones or by their deposits. The current and recent Martian temperatures and atmospheric conditions would not allow for water to be stable at the surface for extended periods of time: it is so cold that the water would freeze, and then it would sublime quickly, because the air is very thin and dry. These gullies could have formed under a different climate, or maybe by repeated bursts of transient fluids. Current leading hypotheses explaining the origin of gullies includes erosion from seepage or eruption of water from a subsurface aquifer, melting of ground ice, or dust-blanketed surface snow.
Evidence of subsurface water has been found by the Mars rover Spirit at the location where the rover remains stuck.
Paul Spudis provides a very detailed analysis of the recently released LCROSS lunar results. Key quote:
The Near-IR spectrometers on the LCROSS shepherding satellite detected abundant water (H2O) but also hydrogen sulfide (H2S), ammonia (NH3), methanol (CH3OH), methane (CH4), ethylene (C2H4) and sulfur dioxide (SO2). The uv-vis spectrometer found carbon dioxide (CO2), sodium, silver, and cyanide (CN). Aboard the distant LRO spacecraft, the ultraviolet LAMP imager detected hydrogen (H2), nitrogen, carbon monoxide (CO), sodium, mercury, zinc, gold (!), and calcium. But water, present in quantities between 5 and 10 weight percent, is the most abundant volatile substance present.
A paper published on Saturday in the Journal of Geophysical Research – Planets of the American Geophysical Union, scientists suggest that the polygonal shaped cracks seen in the crater floors on many Martian craters could be evidence of ancient lakes. The evidence also suggests that the lakes were formed by the impact that created the crater. The energy of the impact melted underground ice to form a temporary lake inside the crater, which eventually dries out, leaving behind the polygons. From the abstract:
We propose desiccation to be a dominant mechanism for the formation of Crater Floor Polygons without ruling out thermal contraction as a possible contributor in some cases. This implies that lakes or water-rich sediments occupied the craters in the past. Many such aqueous environments have no apparent external source of water, and thus, hydrothermal processes occurring shortly after the impact event may be viable explanations for the observed evidence.
These Mars Reconnaissance Orbiter images show in increasing magnification a puzzling feature in the southeast part of a ice mound in Louth Crater on Mars. Located at 70 degrees north latitude, this is the farthest south that scientists have found permanent water ice. The close-up image suggests melting ice with the draining water running down hill to the south, though on Mars the low air pressure would cause any liquid water to evaporate instantly. Key quote:
These may be the crests of partially defrosted dark sand dunes or perhaps some other feature that we do not understand. This is the only area on Louth where these enigmatic ridges are found.
Scientists studying Apollo lunar samples have found evidence that most of the Moon appears very dry, with no water at all. These results obviously contradict the recent findings of water in the craters near the lunar poles, and will require some explaining.
Radar images from Lunar Reconnaissance Orbiter appear to show deposits of approximately 1.6 trillion pounds of water ice on the Moon.
Water vapor detected in deep space, first near the carbon star V Cygni and second in two dark starless cores. The second detection is a first time water has been seen in these black clouds. Fun quote from the abstract of the first paper notes how the detection “raises the intriguing possibility that the observed water is produced by the vapourisation of orbiting comets or dwarf planets.”
Saturday’s weekly dump of publications from the American Geophysical Union also included a paper that showed visual proof of avalanches on Mars! In this case, the location is Russell Crater, “a large crater in the southern hemisphere that exposes a large dune field in its center.” The avalanches occur because a frost layer made up of dry ice and a little bit of frozen water builds up on the crest of the dunes. When that frost melts, dark streaks about three to six feet wide and about 150 feet long appear, flowing downhill. The scientists believe these are avalanches made up of “a mixing of sand, dust, and unstable CO2 gas.”
Before and after shots of the dark streaks flowing down the dune.
Close-ups of the streaks, before and after.
